docs: def supported_languages(self):
          """ dict: All supported language prefixes on the MediaWiki site
  
              Note:
                  Not Settable """
          if self.__supported_languages is None:
              res = self.wiki_request({"meta": "siteinfo", "siprop": "languages"})
              tmp = res["query"]["languages"]
              supported = {lang["code"]: lang["*"] for lang in tmp}
              self.__supported_languages = supported
          return self.__supported_languages